#include <stdio.h>

void* My_strncat(char* dst, char* src, size_t num)
{
    while (*dst)
    {
        dst++;
    }
    
    while (*src && num)
    {
        num--;
        //将数据转按个数要求过去
        *dst++ = *src++;
    }
    //补0
    while (num--)
    {
        *dst++ = '\0';
    }
    //补 \0
    *dst = '\0';
}  

int main()
{
    char arr1[] = "Wang Yi Ming";
    char arr2[30] = "Tang Li Bin meet ";
    My_strncat(arr2, arr1, 12);
    printf("%s", arr2);

    return 0;
}